G P Samsa

University of North Carolina at Chapel Hill, North Carolina, United States

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Publications (16)174.89 Total impact

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    ABSTRACT: To identify patient-care practices related to an increased prevalence of hepatitis C virus (HCV) infection among chronic hemodialysis patients. Survey. Chronic hemodialysis facilities in the United States. Equal-probability 2-stage cluster sampling was used to select 87 facilities from all Medicare-approved providers treating 30-150 patients; 53 facilities and 2,933 of 3,680 eligible patients agreed to participate. Patients were tested for HCV antibody and HCV RNA. Data on patient-care practices were collected using direct observation. The overall prevalence of HCV infection was 9.9% (95% confidence interval [CI], 8.2%-11.6%); only 2 of 294 HCV-positive patients were detected solely by HCV RNA testing. After adjusting for non-dialysis-related HCV risk factors, patient-care practices independently associated with a higher prevalence of HCV infection included reusing priming receptacles without disinfection (odds ratio [OR], 2.3 [95% CI, 1.4-3.9]), handling blood specimens adjacent to medications and clean supplies (OR, 2.2 [95% CI, 1.3-3.6]), and using mobile carts to deliver injectable medications (OR, 1.7 [95% CI, 1.0-2.8]). Independently related facility covariates were at least 10% patient HCV infection prevalence (OR, 3.0 [95% CI, 1.8-5.2]), patient-to-staff ratio of at least 7 : 1 (OR, 2.4 [95% CI, 1.4-4.1]), and treatment duration of at least 2 years (OR, 2.4 [95% CI, 1.3-4.4]). This study provides the first epidemiologic evidence of associations between specific patient-care practices and higher HCV infection prevalence among hemodialysis patients. Staff should review practices to ensure that hemodialysis-specific infection control practices are being implemented, especially handling clean and contaminated items in separate areas, reusing items only if disinfected, and prohibiting mobile medication and clean supply carts within treatment areas.
    Infection Control and Hospital Epidemiology 05/2011; 32(5):415-24. · 4.02 Impact Factor
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    ABSTRACT: Nosocomial pneumonia is the leading cause of mortality attributed to nosocomial infection. Appropriate empirical therapy has been associated with improved survival, but data are limited regarding the etiologic agents of hospital-acquired pneumonia in nonventilated patients (HAP). This evaluation assessed whether the currently recommended empirical therapy is appropriate for both ventilator-associated pneumonia (VAP) and HAP by evaluating the infecting flora. Prospectively collected hospitalwide surveillance data was obtained by infection control professionals using standard Centers for Disease Control and Prevention definitions. A tertiary care academic hospital. All patients admitted from 2000 through 2003. A total of 588 episodes of pneumonia were reported in 556 patients: 327 episodes of VAP in 309 patients, and 261 episodes of HAP in 247 patients. The infecting flora in ventilated patients included gram-positive cocci (32.0% [oxacillin-susceptible Staphylococcus aureus {OSSA}, 9.25%; oxacillin-resistant Staphylococcus aureus {ORSA}, 17.75%]), gram-negative bacilli (59.0% (Pseudomonas aeruginosa, 17.50%; Stenotrophomonas maltophilia, 6.75%; Acinetobacter species, 7.75%), and miscellaneous pathogens (9.0%). The infecting flora in nonventilated patients included gram-positive cocci (42.59% [OSSA, 13.33%; ORSA, 20.37%]), gram-negative bacilli (39.63% [P. aeruginosa, 9.26%; S. maltophilia, 1.11%; Acinetobacter species, 3.33%), and miscellaneous pathogens (17.78%). Our data demonstrated that patients with HAP, compared with those with VAP, had a similar frequency of infection with ORSA but less commonly had infections due to P. aeruginosa, Acinetobacter species, and S. maltophilia. However, the overall frequency of infection with these pathogens was sufficiently high to warrant the use of empirical therapy likely to be active against them. Our data supports using the currently recommended empirical therapy for both HAP and VAP.
    Infection Control and Hospital Epidemiology 08/2007; 28(7):825-31. · 3.94 Impact Factor
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    ABSTRACT: Health care-associated infections most commonly result from person-to-person transmission via the hands of health care workers. We studied the efficacy of hand hygiene agents (n = 14) following 10-second applications to reduce the level of challenge organisms (Serratia marcescens and MS2 bacteriophage) from the hands of healthy volunteers using the ASTM-E-1174-94 test method. The highest log 10 reductions of S marcescens were achieved with agents containing chlorhexidine gluconate (CHG), triclosan, benzethonium chloride, and the controls, tap water alone and nonantimicrobial soap and water (episode 1 of hand hygiene, 1.60-2.01; episode 10, 1.60-3.63). Handwipes but not alcohol-based handrubs were significantly inferior from these agents after a single episode of hand hygiene, but both groups were significantly inferior after 10 episodes. After a single episode of hand hygiene, alcohol/silver iodide, CHG, triclosan, and benzethonium chloride were similar to the controls in reduction of MS2, but, in general, handwipes and alcohol-based handrubs showed significantly lower efficacy. After 10 episodes, only benzethonium chloride (1.33) performed as well as the controls (1.59-1.89) in the reduction of MS2. Antimicrobial handwashing agents were the most efficacious in bacterial removal, whereas waterless agents showed variable efficacy. Alcohol-based handrubs compared with other products demonstrated better efficacy after a single episode of hand hygiene than after 10 episodes. Effective hand hygiene for high levels of viral contamination with a nonenveloped virus was best achieved by physical removal with a nonantimicrobial soap or tap water alone.
    American Journal of Infection Control 04/2005; 33(2):67-77. · 2.33 Impact Factor
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    ABSTRACT: We compared the relative frequency of pathogens isolated from 1985 to 1989 (N = 4358) with those isolated from 1980 to 1984 (N = 5290) in a university hospital to determine trends in the relative importance of pathogens causing nosocomial infection. Our study was based on surveillance data prospectively obtained between 1980 and 1989 from a 600-bed university hospital. Statistically significant trends occurring from 1980 to 1984 to 1985 to 1989 were determined by chi 2 tests with Bonferroni corrections (i.e., p less than [0.05/17]). Overall an increased frequency of isolation occurred for Candida and other yeasts and for Haemophilus species. A decreased frequency was noted for Proteus species, non-Bacteroides anaerobes, and Serratia species. Comparison of 1985 to 1989 with 1980 to 1984 revealed that the most significant change in nosocomial pathogens was the marked increase in infections with yeast, principally Candida species. Candida and other yeast infections increased 40%, from 7.6% (rank, 5) to 10.6% (rank, 3) of all pathogens isolated. Increases, which occurred in urine, blood, and wound isolates, were especially marked among surgical patients. In addition, a significant increase was noted among blood isolates in the isolation of yeast other than Candida albicans. We conclude that Candida and other yeasts are being isolated increasingly as causative agents of nosocomial infection.
    American Journal of Infection Control 09/1992; 20(4):192-7. · 2.33 Impact Factor
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    ABSTRACT: To obtain a quantitative estimate of the impact on infectious complications of using transparent dressings with intravenous catheters. Meta-analysis of all studies published in the English literature, including abstracts, letters, and reports that examined the primary research question of infection risks associated with transparent compared with gauze dressings for use on central and peripheral venous catheters. Studies were identified by use of the MEDLINE database using the indexing terms occlusive dressings, transparent dressings, and infection and by review of referenced bibliographies. Seven of the 15 studies (47%) of central venous catheters and seven of 12 studies (58%) of peripheral catheters met our inclusion criteria for analysis. All studies used a prospective cohort design, utilized hospitalized patients, and reported at least one of our defined outcomes. Data for each study were abstracted independently by three investigators. At least three studies were used in the analysis of each outcome. Applying a Mantel-Haenszel chi 2 analysis, use of transparent dressings on central venous catheters was significantly associated with an elevated relative risk (RR) of catheter tip infection (RR = 1.78; 95% confidence interval [CI], 1.38 to 2.30). Catheter-related sepsis (RR = 1.69; 95% CI, 0.97 to 2.95) and bacteremia (RR = 1.63; 95% CI, 0.76 to 3.47) were both associated with an elevated RR. Use of transparent dressings on peripheral catheters was associated with an elevated RR of catheter-tip infection (RR = 1.53; 95% CI, 1.18 to 1.99) but not phlebitis (RR = 1.02; 95% CI, 0.86 to 1.20), infiltration (RR = 1.12; 95% CI, 0.92 to 1.37), or skin colonization (RR = 0.99; 95% CI, 0.90 to 1.09). The results demonstrated a significantly increased risk of catheter-tip infection with the use of transparent compared with gauze dressings when used with either central or peripheral catheters. An increased risk of bacteremia and catheter sepsis associated with the use of transparent compared with gauze dressings for use on central venous catheters was suggested.
    JAMA The Journal of the American Medical Association 05/1992; 267(15):2072-6. · 30.39 Impact Factor
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    ABSTRACT: As part of a prospective cohort study initiated in 1983, the human immunodeficiency virus type 1 (HIV-1) status has been periodically determined for patients with clotting disorders (hemophilia A or B, von Willebrand's disease, miscellaneous). The University of North Carolina Hospitals has conducted comprehensive surveillance for nosocomial infections (NI) using modified Centers for Disease Control criteria since 1980 and entered this information in a computerized data base. Cross-matching of our NI data base and hemophiliac/HIV-1 study data base for the time period 1980-1989 revealed that 13 NI occurred in 11 patients during 659 hospitalizations (5,723 hospital days). NI rates per 100 admissions (per 1,000 hospital days) by HIV-1 status were as follows: HIV-1 negative = 0.91 (1.18), HIV-1 positive pre-AIDS = 1.65 (1.84), and AIDS = 6.67 (6.48). NI occurred with a similar frequency in HIV-1 positive pre-AIDS hemophiliacs and HIV-1 negative hemophiliacs (Fisher's exact test, p greater than 0.10). However, NI occurred more frequently in hemophiliacs with AIDS versus HIV-1 positive or negative hemophiliacs (Fisher's exact test, p less than 0.05). We conclude that HIV-1 infection does not appreciably alter the risk of developing a NI, but that patients who have progressed to AIDS are at significantly increased risk of developing a NI per hospital day or per hospitalization.
    The American Journal of Medicine 10/1991; 91(3B):206S-212S. · 5.30 Impact Factor
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    ABSTRACT: The effects on the quantity and quality of antimicrobial drug use of removing an antimicrobial restriction policy are reported. Monthly totals for the number of courses of antimicrobial therapy and expenditures based on grams used were obtained from pharmacy records on adult inpatients for a portion (July-December 1987) of the restriction policy term and for the six months (July-December 1988) immediately after the policy ended. Data were obtained for nine restricted drugs and for three that were never restricted. Retrospective drug-use reviews were conducted for ceftazidime and imipenem-cilastatin. For the restricted agents, the total number of courses of therapy increased by 158% after the restriction policy was removed, and total expenditures increased by 103%. There were no significant changes in the number of courses of therapy or cost for the unrestricted antimicrobials. In the postrestriction period, ceftazidime and imipenem-cilastatin were used more often in patients who were less critically ill. Inappropriate use of imipenem-cilastatin occurred significantly more often after the restrictions were removed. Other factors potentially affecting the use of antimicrobials, such as patient age and the incidence of nosocomial infections, did not differ substantially between the two periods. The removal of an antimicrobial restriction policy resulted in increased use of and higher expenditures for previously restricted agents, as well as an increase in the inappropriate use of at least one agent.
    American journal of hospital pharmacy 07/1991; 48(6):1220-7.
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    ABSTRACT: We analyzed all cases of tuberculosis reported in North Carolina between 1966 and 1986, and related the incidence rate of tuberculosis (per 100,000 population) to age (0 to 4 years, 7.59; 5 to 14 years, 3.44; 15 to 24 years, 6.30; 25 to 44 years, 15.92; 45 to 64 years, 33.85; greater than 65 years, 51.54), race (white 9.03, nonwhite 47.40), and gender (male 25.49, female 11.25). Over the 21-year study period the annual number of cases declined from 1,248 to 711 (43%), and the incidence rate from 25.56 to 11.25 (56%). Although the incidence rate of tuberculosis fell for all subgroups, nonwhites continued to have an incidence rate 3.2 to 22.5 times higher than whites, depending on age. The standardized morbidity ratio (SMR) (by age, race, and gender) of tuberculosis in the eastern region of North Carolina was nearly twice that of the western region and unexplainable by its demographics. Between 1983 and 1986 only a small percentage of cases of tuberculosis in North Carolina were accounted for by migrant farm workers (1.7% to 2.7%) and patients with the acquired immunodeficiency syndrome (less than 1%). Tuberculosis is increasingly a disease of the elderly, especially nonwhite men. Tuberculosis is a geographically and demographically focal disease in North Carolina, and preventive strategies should be appropriately targeted.
    Southern Medical Journal 11/1989; 82(10):1204-14. · 1.12 Impact Factor
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    ABSTRACT: Prospective surveillance for nosocomial infections was performed for a five-year admission cohort (1980-1984) at North Carolina Memorial Hospital. One or more nosocomial infections developed in 2,662 patients (2.6%) from 102,206 patients at risk; greater than or equal to 2 nosocomial infections developed in 775 of these 2,662 patients (29.1%), and greater than or equal to 3 nosocomial infections in 304 of 775 patients with greater than or equal to 2 infections (39.2%). Hospital stay was significantly prolonged for infected compared with never-infected patients (38.1 vs. 7.9 days, p less than 0.0001) and for multiply-infected versus once-infected patients (57.9 vs. 30.0 days, p less than 0.0001). Total nosocomial infections numbered 4,031 with 2,144 multiple infections (53%); the average number of nosocomial infections per infected patient was 1.5 (4,031 infections in 2,662 patients). Among all nosocomial infections, 64% of bacteremias, 55% of respiratory infections, 55% of surgical wound infections, and 40% of urinary tract infections occurred in patients with multiple nosocomial infections. Surgical patients had 56% of multiple infections. Intensive care unit patients had significantly more multiple infections than non-intensive care unit patients. Nosocomial infections in intensive care unit patients were 71% multiple nosocomial infections. The probability of developing multiple infections was 11 times greater after the first infection occurred. This emphasizes the need to prevent initial nosocomial infections and to identify risk factors for multiple nosocomial infections. Determining risk factors for multiple nosocomial infections could focus infection control efforts on a subpopulation of patients who acquire over 50% of all nosocomial infections and who have significantly prolonged and costly hospital stays.
    American Journal of Epidemiology 11/1989; 130(4):769-80. · 4.98 Impact Factor
  • W A Rutala, R L Odette, G P Samsa
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    ABSTRACT: In July 1987 and January 1988, forty-six percent (441/955) of randomly selected US hospitals responded to a questionnaire intended to identify their waste disposal practices. Survey responses were received from hospitals in 48 states. United States hospitals generated a median of 6.93 kg of hospital waste per patient per day and infectious waste made up 15% of the total hospital waste. Most hospitals (greater than 90%) considered blood, microbiology, "sharps," communicable disease isolation, pathology, autopsy, and contaminated animal carcass waste as infectious. Other sources of hospital waste that were commonly (greater than 80%) designated infectious were surgical, dialysis, and miscellaneous laboratory waste. The infectious waste was normally (80%) treated via incineration or steam sterilization before disposal, whereas noninfectious waste was discarded directly in a sanitary landfill. Eight-two percent of these US hospitals are discarding blood, microbiology, sharps, pathology, and contaminated animal carcass waste in accordance with the Centers for Disease Control's recommendations, while the compliance rate for the Environmental Protection Agency's recommendations (excluding optional waste) is 75%. No hospital could identify an infection problem (excluding needle-stick injuries) that was attributable to the disposal of infectious waste. While the management of infectious waste by US hospitals is generally consistent with the Centers for Disease Control's guidelines, many hospitals employ overly inclusive definitions of infectious waste.
    JAMA The Journal of the American Medical Association 01/1989; 262(12):1635-40. · 30.39 Impact Factor
  • S M Saviteer, G P Samsa, W A Rutala
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    ABSTRACT: Elderly patients have been shown to have an increased risk of acquiring nosocomial infection per hospital admission. To determine if the length of stay accounts for this risk, daily infection rates were computed per decade of life and rates for patients over and under 60 were compared using risk ratios. Four thousand thirty-one nosocomial infections in 2,567 patients were identified for a 1980 through 1984 admission cohort in an acute-care hospital. The daily infection rates were 0.59 percent in patients over age 60 and 0.40 percent in younger patients (relative risk = 1.49). The daily incidences of urinary tract infections, respiratory infections, and septicemias were all significantly increased in elderly patients with risk ratios of 2.78, 2.07, and 1.36, respectively. Further analysis revealed that elderly patients experienced significantly more nosocomial infections for each day of hospitalization after Day 7. These data show that elderly patients experience an increased daily rate of nosocomial infection, and suggest that efforts be directed at identifying clinical conditions that predispose this population to hospital-acquired infections.
    The American Journal of Medicine 05/1988; 84(4):661-6. · 5.30 Impact Factor
  • E C Cole, W A Rutala, G P Samsa
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    ABSTRACT: An initial collaborative study of the AOAC use-dilution method (UDM), used for bactericidal disinfectant efficacy testing, demonstrated extreme variability of test results among the 18 laboratories testing identical hospital disinfectants. In an effort to improve the method, 32 changes were made by the UDM Task Force. These changes represented improvements in quality assurance practices and elimination of method variability; however, the basic framework of the method was retained. A second collaborative trial was conducted to determine if the interlaboratory variability of test results could be reduced to an acceptable level using the modified UDM. Twelve of the original 18 laboratories participated in the second study. Each laboratory processed 60 penicylinders (P) for each of the 6 randomly selected, federally registered disinfectants and 3 test organisms (Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa). The number of positive penicylinders (greater than 1 positive P/60 replicates = failure) for the 6 products when P. aeruginosa was used as the challenge organism ranged 1-30, 0-36, 0-15, 0-5, 0-3, and 0-60 for the 3 quaternaries and 3 phenolics, respectively. The results of the variance components analysis for P. aeruginosa and the other 2 organisms showed that the variance components for laboratories were not significantly reduced for any organism in this study. Such interlaboratory variability of results questions the use of the original or the modified UDM for registration purposes.
    Journal - Association of Official Analytical Chemists 01/1988; 71(6):1187-94.
  • L E Price, W A Rutala, G P Samsa
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    ABSTRACT: Tuberculosis (TB) skin testing practices and the prevalence and inherent risk of TB infection among hospital employees in 167 North Carolina (NC) hospitals were determined from a 79% (132/167) response to a tuberculosis screening questionnaire. Preemployment TB skin testing was performed by 98% of responding hospitals, primarily (87%) by the Mantoux method. TB skin test reactions of greater than or equal to 10 mm were interpreted as significant by 72% and at the appropriate time interval of 48 to 72 hours after administration by 80%. The booster test was routinely performed in 12% of the hospitals. TB infection prevalence among new employees during 1983 was 6.3% (260/4137) in 30 hospitals supplying these data. A positive correlation was noted between employee infection prevalence and county TB case rates (P = .014). Skin test conversion data from 56 hospitals across the state revealed a five year mean conversion rate of 1.14% among 71,253 personnel. There was an association between the incidence of TB in the general population and the frequency of conversions among hospital employees in corresponding geographical regions. Similarly, the incidence of TB among approximately 100,000 NC hospital employees in 1983 and 1984 was less than the incidence in the general population. These associations suggest that the incidence of TB infection among hospital personnel may reflect the prevalence of tuberculosis in the community rather than an occupational hazard. Annual TB skin testing of hospital employees may be justified in eastern North Carolina where the incidence of tuberculosis (22-30 cases/100,000) is greater than the national average and where the risk of new TB infection among hospital employees is relatively common (greater than or equal to 1.5%).
    Infection control: IC 04/1987; 8(3):97-101.
  • E C Cole, W A Rutala, G P Samsa
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    ABSTRACT: An interlaboratory study was conducted to evaluate a method of standardizing bacterial numbers on penicylinders used in the AOAC use-dilution method (4.007-4.015) of disinfectant testing. Eight participating laboratories followed a broth adjustment method using their media and stock cultures of Staphylococcus aureus ATCC 6538, Salmonella choleraesuis ATCC 10708, and Pseudomonas aeruginosa ATCC 15442. The culture broths that were used to inoculate the penicylinders were incubated for 48 h at 37 degrees C after several (4-6) 24 h passages. McFarland turbidity standards of 1.0 and 0.5 were used to adjust visually the cultures of S. aureus and P. aeruginosa, respectively. S. choleraesuis was used undiluted. The results showed significant variability in numbers of test bacteria which adhered to the penicylinders, with mean values of 1.6 X 10(6) for S. choleraesuis, 3.5 X 10(6) for S. aureus, and 8.2 X 10(6) for P. aeruginosa. The results from collaborating laboratories attempting standardization of bacterial numbers on penicylinders demonstrated significant interlaboratory and cylinder variation for all 3 test organisms.
    Journal - Association of Official Analytical Chemists 01/1987; 70(4):635-7.
  • New England Journal of Medicine 06/1986; 314(21):1393. · 54.42 Impact Factor
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    ABSTRACT: Factors associated with lack of antibody response to the hepatitis B virus plasma vaccine were retrospectively evaluated by means of a logistic regression in 194 previously seronegative staff members of a community hospital. All subjects had received three doses of vaccine by intramuscular buttock injection using a 1-in, 23-gauge needle. Overall, only 55.7% of subjects developed detectable antibody to hepatitis B surface antigen in serum after immunization. The weight-height index served as a surrogate measure of obesity. Predictors of poor immunogenic response to hepatitis B vaccine included higher weight-height index, older age, and vaccine batch. Sex, race, timing of vaccine doses, and timing of postimmunization determination of antibody to hepatitis B surface antigen were not predictors of vaccine efficacy.
    JAMA The Journal of the American Medical Association 01/1986; 254(22):3187-9. · 30.39 Impact Factor